FELLER, M. N. New condition of harmonicity of functions of infinitely many variables (translation nonpositive case). Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 11, p. 1602–1605, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5605. Acesso em: 5 dec. 2025.